Abstract
ER body is an ER derived organelle, which might be responsible for defense systems, because they are induced by wounding. A proteomic analysis showed that both PYK10 and PBP1 (At1g16420) were decreased in their levels in Arabidopsis nai1 mutant, which has no ER bodies. PYK10, which is localized in ER bodies, is a beta-glucosidase with three oligosaccharide chains. On the other hand, PBP1 is a cytosolic lectin.
During incubation of the extract from Arabidopsis roots, PYK10 molecules were separated into two forms; active form and inactive form. The amount of active form of PYK10 was less than that of inactive form of PYK10. Most of the active PYK10 molecules formed huge aggregates during the incubation. An immunoprecipitation with anti-PYK10 antibodies revealed that PBP1 was interacted with PYK10. These results suggest that PBP1 is responsible for aggregation of inactive PYK10, but not for aggregation of active PYK10.
